Only if you neglect your studies in favor of the relationship. In other words, if someone skips classes, doesn't turn in papers, doesn't study for exams, and doesn't show up for group projects because they'd rather spend time with their BF/GF, then yes, it could. Or if the person stays out too late with the BF/GF and is too tired to concentrate in classes and lectures, then yes.
On the other hand, if there is a balance and the person allows adequate time for studies and classes and sees their GF/BF when time allows, then there's no reason at all for it to negatively impact your studies. I had a serious BF in college and I still managed to maintain a high B average and turn in all school work, and I seldom missed class.
"Advice is what we ask for when we already know the answer but wish we didn't." - Erica Jong